1. Field of the Invention
The invention relates to a press plate mounting apparatus and, more particularly, to a press plate mounting apparatus capable of mounting a press plate easily and accurately onto an outer peripheral surface of a plate cylinder.
2. Description of the Related Art
A generally cylindrical plate cylinder of a rotary press is designed so that a sheet-shaped press plate having a print face region with projections and depressions can be mounted onto an outer peripheral surface of the plate cylinder. The plate cylinder mounting operation is performed manually in many cases.
In such a case, however, it is not easy to accurately mount a sheet-like press plate onto the outer peripheral surface of a cylindrical plate cylinder. That is, there is a drawback that a press plate is likely to have a positional deviation from a precise position on the outer peripheral surface of the plate cylinder in the directions of an axis or the circumferential directions when mounted on the outer peripheral surface of the plate cylinder.
The invention has been accomplished in view of the aforementioned drawback. It is an object of the invention to provide a press plate mounting apparatus capable of mounting a press plate easily and accurately onto an outer peripheral surface of a plate cylinder.
In order to achieve the aforementioned object, the invention adopts a construction as follows. That is, the press plate mounting apparatus of the invention includes a press plate placement portion capable of holding a press plate having a partially formed print face region, and a plate cylinder holding portion that rotatably holds a plate cylinder onto which the press plate is mounted. The apparatus mounts the press plate onto an outer peripheral surface of the plate cylinder by rotating the plate cylinder while causing the press plate to contact the outer peripheral surface of the plate cylinder. A protrusion is provided in a non-print region of the press plate. The press plate placement portion includes a suction surface that sucks the print face region, and a positioning member provided at a position outward of the suction surface and extending in a predetermined direction. The positioning member is able to contact the protrusion when the press plate is held at a predetermined position. The positioning member has a scale that makes it possible to visually check a positional deviation of the press plate in the predetermined direction. According to this construction, when the press plate is set on the press plate placement portion, the positioning of the press plate in the direction perpendicular to the aforementioned predetermined direction can be easily accomplished by causing the protrusion of the press plate to contact the positioning member. Furthermore, using the scale, the positioning of the press plate in the predetermined direction can also be easily accomplished. Therefore, the press plate can be reliably held on the press plate placement portion without a positional deviation in the directions of the plane. While this state is maintained, the plate cylinder is rotated with the press plate contacting the outer peripheral surface of the plate cylinder. In this manner, the press plate can be easily and precisely mounted on the outer peripheral surface of the plate cylinder.
In the invention, it is possible to adopt a construction in which the press plate placement portion is provided rotatably about an end portion of the press plate placement portion located toward the plate cylinder holding portion, and allows the press plate to be set on the press plate placement portion with the suction surface facing upward. This construction further facilitates the setting of the press plate onto the press plate placement portion.
It is also possible to adopt a construction in which the press plate placement portion is provided with a floatation restricting member capable of restricting separation of the print face region from the suction surface. This construction makes it possible to prevent separation of the press plate from the press plate placement portion when the press plate placement portion is turned.
In this specification, the term xe2x80x9cnormal position of the press plate placement portionxe2x80x9d means a setting position of the press plate on the press plate placement portion which makes it possible to precisely mount the press plate in the circumferential directions of the outer peripheral surface of the plate cylinder and the directions of an axis thereof.